Income Taxes - Income Tax Rate Reconciliation (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Federal statutory tax rate	34.00%	34.00%	34.00%
Difference between total income tax expense and the amount computed by applying the statutory Federal income tax rate 33% to income before taxes:
Income tax at statutory rate	$ 2,912	$ 2,139	$ 2,382
State income taxes, net of Federal benefit	452	307	472
Oil and mineral depletion	(385)	(450)	(620)
Valuation allowance - land contribution	0	0	0
Other, net	(282)	90	489
Total provision	$ 2,697us-gaap_IncomeTaxExpenseBenefit	$ 2,086us-gaap_IncomeTaxExpenseBenefit	$ 2,723us-gaap_IncomeTaxExpenseBenefit

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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